Northern Lights, also known as aurora borealis could be visible in regions such as in the northern parts of Illinois and Pennsylvania in the US.
Try this PYQ:
What is a coma, in the context of Astronomy?
(a) Bright half of material on the comet
(b) Long tail of dust
(c) Two asteroids orbiting each other
(d) Two planets orbiting each other
Aurora
- Auroras occur when charged particles ejected from the Sun’s surface — called the solar wind — enter the Earth’s atmosphere.
- While flowing toward Earth, the fast-moving solar wind carries with it the Sun’s magnetic field, which disrupts the magnetosphere — the region of space around Earth in which the magnetic field of our planet is dominant.
- When the Sun’s magnetic field approaches Earth, the protective magnetic field radiating from our planet’s poles deflects the former, thus shielding life on Earth.
- However, as this happens, the protective fields couple together to form funnels, through which charged solar wind particles are able to stream down to the poles.
- At the north and south poles, the charged particles interact with different gases in the atmosphere, causing a display of light in the sky.
- This display, known as an aurora, is seen from the Earth’s high latitude regions (called the auroral oval), and is active all year round.
Behind the name
- In the northern part of our globe, the polar lights are called aurora borealis or Northern Lights and are seen from the US (Alaska), Canada, Iceland, Greenland, Norway, Sweden and Finland.
- In the south, they are called aurora australis or southern lights and are visible from high latitudes in Antarctica, Chile, Argentina, New Zealand and Australia.
Where is it observed?
- Generally, the auroral oval is usually witnessed far up in the Polar Regions or the high latitude regions of Europe, like in Norway.
- But occasionally, the oval expands, and the lights become visible at lower latitudes.
- This happens during periods of high solar activity, such as the arrival of solar storms.
- Solar activities include solar flares, solar energetic particles, high-speed solar wind and Coronal Mass Ejections (CME).
